Sewing machine



March 30, 1948. M. G. IVANDICK SEWING MACHINE Filed Jan. 1, 1945 2Sheets-Sheet 1 mawe ZiF A;

March 30, 1948. M. G. lVANDlCK SEWING MACHINE Filed Jan. 1, 1945Sheets-Sheet 2 Patented Mar. 30, 1948 SEWING MACHINE Matthew G.Ivandick, Rockford, 111., assignor to Free Sewing Machine 00., Rockford,11]., a corporation of Illinois Application January 1, 1945, Serial No.570,869

4 Claims. (01. 112-241) This invention relates to sewing machines, andis more particularly concerned with a one-to-one constant speed drive,as distinguished from the conventional two-to-one constant speed drivesand the one-to-one variable speed drives.

In the old machines having one-to-one variable speed drives andtwo-to-one constant speed drives, it has been necessary to connect thecloth feed control with the upper shaft, and that necessarilycomplicates the construction considerably, making these machines farmore expensive to manufacture, much heavier, and more apt to get out oforder and require expensive repairing periodically. These considerationsalone, it would appear, should have dictated the invention andproduction long ago of a commercially acceptable one-to-one constantspeed drive machine, but they are by no means the only considerations;there are the following:

(1) A constant speed one-to-one drive reduces vibration, therebyproducing a smoother runnin machine;

(2) A constant speed one-to-one drive means more power on the lowershaft turning the hook;

(3) Constant speed one-to-one drive means a reduction in the speed ofthe lower shaft, thus prolonging the life of the machine;

(4) Constant speed one-to-one drive insures better upper thread control,as compared with a variable speed one-to-one drive wherein the bobbincase slows down and speeds up in each rotation, causing jerky and unevenshedding action, and

(5) Constant speed one-to-one drive permits more accurate timing betweenthe hook and take-up.

One-to-one ratio drives havebeen disclosed in patents, but, so far as Iam aware, there has been no commercially successful sewing machineembodying such a drive, and in view of the numerous advantages justmentioned, the conclusion is inescapable that the one-to-one ratiodrives disclosed in the patents were not practical for certain reasons.It is, therefore, the principal object of my invention to provide apractical form of one-to-one constant speed drive for sewing machines.

The salient feature of my invention is the provision of a novel cammeans for actuating the take-up arm in the correct timed relationship tothe operation of the needle bar and rotary hook, the take-up arm beingpreferably springpressed to move upwardly and having a roller mountedthereon and operating as a follower in the cam track in the face of arotary cam turning with the needle bar operating shaft. The crank pincooperating with the pitman rod for reciprocating the needle bar intimed relation to the turning of the upper shaft is, in accordance withmy invention, utilized also to turn the cam and support it in the properplane for operation of the take-up arm.

The invention is illustrated in the accompanying drawings, in which Fig.1 is a view of a sewing machine partly in front elevation and partly invertical section, embodying the one-to-one constant speed drive inaccordance with my invention;

Figs. 2, 3 and 4 are end views of the machine. showing the parts indifferent relationships throughout a single revolution of the upper andlower shafts, and

Fig. 5 is a horizontal section on the line 5--5 of Fig. 2.

The same reference numerals are applied to corresponding partsthroughout the views.

In the drawings, the reference numeral 8 designates the cloth plate, 9the column projecting upwardly therefrom, and I0 the arm from which theneedle bar ll carrying the needle l2 extends for operation. The presserbar l3, shown in Figs. 2, 3 and 4 behind the needle bar H, carries theusual pressure foot l4 that is held down in contact with the cloth plateunder spring pressure in the usual way, but may be raised to anout-ofthe-way position by operation of the lift lever I5 in thewell-known manner to permit entry or removal of work. Indicated at IS inFig. 1 are the usual cloth feed dogs operable through slots I! in thecloth plate under the presser foot, and I8 is the rotary hook comprisinga thread loop carrier supporting for relative rotational movement abobbin case base [9 which in turn rotatably supports a bobbin retainedin the base by a case in the well-known manner as illustrated, forexample, in the Southam et a1. Patent 2,065,349. The rotary hook I8 isturned by means of a lower shaft 20 supported in bearings under thecloth plate and connected by gears 2| with a vertical shaft 22 in thecolumn 9 to operate in the desired one-to-one relation with the uppershaft 23, with which the shaft 22 is connected by gears 24. A handwheel25 is operatively connected with a gear 26 meshing with one of the gears2| to permit manual operation of the machine. Suitable drive means isprovided for power operation of the machine, a pulley 25a beingindicated in frictional contact with the handwheel 25, the shaft 25bbeing driven by an electric motor (not shown).

This pulley may be disengaged from the handwheel 25 and engaged with abobbin winder (not shown) in the manner disclosed in my co-pendingapplication, Serial No. 529,131, filed April 1, 1944, which resulted inmy Patent No. 2,417,417, issued March 18, 1947. While the speed of themotor driving the pulley 25a may be varied by means of a rheostat in theconventional manner, it should be clear that for any given speed'settingof the rheostat the shafts 20 and 23 are driven in a one-to-one constantspeed relationship.

The shaft 21 disposed in parallel relation to the lower shaft 20 underthe cloth plate is provided for adjusting the stitch regulating andreversing cam or cross-head 28 that is disposeddir'ectly beneath and inclose proximity to the rotary hook IS, in accordance with the disclosureinmy co-v pending application, Serial No. 545,778, filed July 20, 1944,which resulted in Patent No. 2,420,480, issued May 13, 1947. A pin 29carried on the lower end of an arm 36 is slidable in a diametri callyextending slot 3| provided in the cam 28.

The upper end of the arm 30 has a circular hole 32 therein rota'tablyreceiving an eccentric 33 that is keyed, as indicated at 34, on the endportion of the shaft 29. Another eccentric 35 is also keyed on the shaft29 with the same key, and-is slidable and rotatable in an elongatedopening 36 provided in a carrier plate 31 on which the cloth feed dogsare mounted, as indicated at 38. The plate'31, as fully disclosed in theco Pending ap plication, is given the same vertical reciprocation at alltimes due to the fact that the eccentric 35 has a fixed throw, but thereciprocatory movement of. the plate 31 and the cloth feed dogs 16 in ahorizontal direction, fore and aft relative'to the cloth plate 3,depends upon the angular adjustment of the cam 28, and the feed is in aforward direction or reverse direction, depending upon the direction ofinclination of the slot 3|. A manually adjustable bell crank lever 39',pivoted as at 40 on the lower end of the column 9, has an arm inside thecolumn connected by means of a link 4| to an arm 42 provided on theinner end of the shaft 21. The lever 39', as dis closed in theco-pending application, is set relative to a scale 43 that isgraduated-in terms" of the number of stitches per inch which the machineis adapted to sew when the lever 39 is set with its pointer indicating aspecified number of stitches per inch on the scale, forward and reversesewing being indicated on the scale-and the scale reading right and leftfrom a zero point at the middle of the scale, which is the neutral pointcorresponding to vertical disposition of the slot'3 I.

The upper shaft 23, which has already been described as driven in aone-to-one ratio relationship with the lower shaft 29, has acounterweighted crank 44 on the outer end thereof that is connected bymeans of a crank pin 45 and-pitman rod 46 with the upper end of theneedle bar H. V The crank pin 45, in accordance with my invention,serves as the support for a cam di'sc 41 in concentric spaced parallelrelationship to the crank 44and immediately behind a cross-bar 48, asbest appears in Figs. 1 and 5. The crossbar 48 has the needle threadtake-up arm 49 pivoted thereon, as indicated at 59, and the pin formingthe pivot 59 serves as a support for'the coiled portion 51 of agrasshopper spring, one arm 52 of which is anchored at its outer cndtothe face plate 53, and the other arm 54 of which has its outer endanchored to the arm 49, whereby normally to tend toturn the armin aclockwise direction relative to the-piv'ot-pin 59. The takeup arm hasthe long end thereof extending through a slot in the face plate 53 forconnection with the needle thread in the usual manner, and the short endof said arm carries a pin 55 which extends through an arcuate slot 56 inthe crossbar 48 and has a roller 51 thereon working in the cam groove 58provided in the outer face of the cam disc 41. The groove 58, as clearlyappears in Figs. 2,3and 4, is of a form concentric with the disc 41 andshaft 23 throughout approximately 180 so that the take-uparm 49 remainsin the lower position throughout approximately 180 turning of the shafts20 and 23 while the follower roller 51 is operating idly in this dwell,as appears i'n'Figs. 2 and 3, which show the disc 41 in two positionsabout 180 apart. The high point 59 of the cam groove is approximately atthe middle of the other 180 portion of said groove, and the take-up arm49 will accordingly be given its full rise in about 90 turning of thedisc 41, as illustrated in Figs. 3 and 4, which show the disc in twopositions approximately 90-apart. The re turn movement of thetake-up'arn 49 likewise occurs in approximately 90 turning of the disc41. Therotary hook l8, when the parts are in the position shown in Fig.2, is taking hold of the loopof thread in theneedle l2 to commence theforming of a stitch, and when the parts are in the position shown inFig. 3 thehook I8 is about to shed the loop. It is between this positionof the hook l8 shown in Fig. 3, and the position approximately 90advanced shown in Fig. 4, that the take-up arm 49 should be operated tocomplete the stitch, leaving the hook 18 of course free to take" hold ofthe next loop when the hook arrives again at the position shown in Fig.2. The take up arm 49 is returned in this interval, allowing the needlel2 to go down on the starting of a new stitch. With myimprovedconstruction, the take-up arm 49 is opera-ted 'smoothlyandpositivelywith close accuracy as to timing with relation to the operation of thehook so that/there is no danger of the needlethread breaking and thestitches are neat and uniform. In passing, it-will,

of course, be understood that the thread going from the usualspool in oron the'arm l0 isfiex; tended through a suitable tension device 60 andcheck spring 64, andis extended from the check spring through theeye 62in the end of thetakeup arm, andfrom there down through the eye of theneedle- 12 in the usual way.

In conclusion, I wish topoint out that the cam disc 41 may if desired[be made having onlythe projectingmarginal cam track portion 53providing acam profile similar to that in the outer portion of thegroove 58 and having a high point at the same angularity as the highpoint 59 in the groove 58, the spring '51 cooperating with the take-uparm to keep-the roller 51 in close contact with said profiled cam trackportion at all times. The operation with such a constructionis'substan'tially the same as withthe other construction, Y

but itis believed it would be moreeconomical to manufacture. on theother hand, the cam disc 41- may be left as shown with 'a two-walled cam1 In a sewing ma hine having a reciprocating needle'and a loop-takercooperating therewith to produce lock-stitches, the combination ofinterconnected upper and lower shafts and drivin means therefor to turnthe shafts at a substan tially constant speed and one-to-one ratio, thelower shaft having driving connections with the loop-taker, a crank onthe upper shaft carrying a crank pin, a pitman rod pivoted thereon and aneedle bar carrying the aforesaid needle operatively connected with saidpitman rod, a needle thread take-up arm pivotally mounted to oscillatein a plane parallel to the plane of rotation of the crank, and a camdisk carried on the crank pin and in coaxial relation to and turningwith the upper shaft and having a cam track thereon extending annularlyrelative to the axis of the upper shaft throughout 360 and cooperatingwith follower means carried directly on the take-up arm to operate thelatter in its thread take-up movements in a predetermined timedrelationship to the operation of the needle and loop-taker.

2. In a sewing machine, the combination with an upper shaft, drive meanstherefor, a crank on said shaft, and a needle bar arranged to bereciprocated in the rotation of said crank in a predetermined angulartimed relationship, said crank having a crank pin thereon pivotallyconnected to a pitman rod which in turn is pivotally con nected to theneedle bar, of a circular cam disc disposed in concentric spacedparallel relation to said crank and connected thereto by said crank pinin such spaced relation, said disc having a cam track groove providedtherein, a follower operable in said groove, a needle thread take-upelement mounted for oscillatory movement in a plane parallel to said camdisc and carrying said follower directly thereon, and spring meanstending normally to move the take-up element in one direction, wherebythe follower on the take-up element is maintained in close contact withone side of the groove in the cam disc for closer timing in theoscillation of said take-up element.

3. In a sewing machine, the combination with an upper shaft, drive meanstherefor, a crank on said shaft, and a needle bar arranged to bereciprocated in the rotation of said crank in a predetermined angulartimed relationship, said crank having a crank pin thereon pivotallyconnected to a pitman rod which in turn is pivotally connected to theneedle bar, of a circular cam disc disposed in concentric speed parallelrelation to said crank and connected thereto by said crank pin in suchspaced relationship, said disc having a cam track provided thereon, afollower engaging said track, a needle thread take-up element pivotedintermediate its ends for oscillatory movement in a plane parallel tosaid cam disc and carrying said follower thereon on one end, and springmeans tending normally to swing the takeup element in one direction tomaintain the follower in close contact with the cam track.

4. In a sewing machine having a reciprocating needle and a loop-takercooperating therewith to produce lock-stitches, the combination ofinterconnected upper and lower shafts and driving means therefor to turnthe shafts at a substantially constant speed and one-to-one ratio, thelower shaft having driving connections with the loop-taker, a crank onthe upper shaft carrying a crank pin, a pitman rod pivoted thereon and aneedle bar carrying the aforesaid needle operatively connected with saidpitman rod, a needle thread take-up arm pivotally mounted to oscillatein a plane parallel to the plane of rotation of the crank, a cam diskcarried on the crank pin and in coaxial relation to and turning with theupper shaft and having a cam track thereon extending annularly relativeto the axis of the upper shaft throughout 360 and cooperating withfollower means carried directly on the take-up arm to operate the latterin its thread take-up movements in a predetermined timed relationship tothe operation of the needle and loop-taker, and spring means tendingnormally to swing the takeup arm in one direction to maintain thefollower means in close contact with the cam track.

MATTHEW G. IVANDICK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 389,788 Bolton Sept. 18, 1888977,630 Hohmann Dec. 6, 1910 1,081,841 Von Korytynski Dec. 16, 1913FOREIGN PATENTS Number Country Date 164,400 Great Britain June 16, 1921437,645 France Apr.-25, 1912

